Currently I feel unable to express my thoughts coherently (or rather, my thoughts themselves resemble breadcrumbs that must be collected together) but I think I might be able to add something about the showing emotion issue... and the social. I'm an INFX relating more to the J than the P.
I have a good friend who I believe is an INFP. He's not very emotionally expressive unless he's with his closest friends and confidants. In most other cases, he gives off a stronger introverted and self-absorbed vibe than most people I've seen and observed -- also me. I on the other hand, simply need to ease myself into a new social enviroment (easier said than done, though) before I can be expressive -- it's even better if I have "anchors", meaning acquaintances, smoothing the process. To simplify what I mean by all this... we both have the potential to be bubbly, serotonin-trigger-happy "laughers" (I'm very fond of laughing), but he needs a higher familiarity and trust threshold to enter that mode.
The above does not, however, mean that he's more stand-offish of us two. I used to be classmates with him (though it should be kept in mind that we were 17 at the time), and during the break-times where we occasionally weren't talking, or spending time together, he was simply self absorbed with doodling, writing, and the like... whereas I was closer to the window pane in the classroom just watching adolescents act as the social creatures they are, and pretty much stand-offish as you get, though I did not find people repulsive or repel them. So you could say that we're both reclusive in our own ways -- I, for example, am occasionally described to be cold and "metallic in emotion" despite being overall more expressive and closer to bubbly.
As for friend making, I think we were both pretty equal in that realm. I'm told that I usually project an air of calmness, for instance -- this was also true in his case, and amplified by his introversion. There isn't much to say about this, after all I'm giving a pair of (by now) young adults' accounts, friendships for us pretty much cropped up by themselves whenever they did and we encountered thought patterns similar to our own in other people.
The moral compass / social ethic issue should be addressed... here's my two bits. Call it my Fe developing, or whatever, but nowadays I frequently find myself more sensitive to how people treat each other and communicate with each other. I've frequently told some other friends of mine off for not communicating healthily with each other or making unfair judgments on each other, An ISP friend, for instance, is particularly fond of doing that, and I find myself trying to tell him about the importance of healthy discussion at a developmental stage where he would rather not care about such fineries and get on with swearing.
All of the above is something that I feel my INFP friend would not do. And yet I feel my ISP friend would, almost subconsciously, alter his communication patterns in his presence. (it should be said of course that the ISP friend of mine also used to be classmates with my INFP friend) This is because I feel the Fi moral compass, while not being direct, has a certain influence on other people despite being a strictly internal faculty. Thus it would seem that both F functions serve social purposes. Also, Fi's sensitivity goes the distance. I've seen him moved to despair, near tears, by some of the darker things we have glimpsed in the enviroments we have been, where I would be either cynical, saddened or outraged. This is because he concentrates of the implications of what he has seen. On the other hand, I'm far more hurt/saddened by offenses directly aimed at my person or close friends, (like when I was teased, again in high school), and concentrate on the implications of those, whereas he finds that sort of thing disgusting.
I feel I could type more, but not now. Hope this has been helpful. Of course, I should add -- I might be entirely off and perhaps I'm the INFP and he's the INFJ.
